Unraveling the early universe's equation of state and primordial black hole production with PTA, BBN, and CMB observations

Qing-Hua Zhu, Zhi-Chao Zhao, Sai Wang +1

Pulsar timing array (PTA) data releases showed strong evidence for a stochastic gravitational-wave background in the nanohertz band. When the signal is interpreted by a scenario of…